Normally if you want to manage your own kernel you would just download the sources you want to use manually, and add an entry to /etc/portage/profile/package.provided and list some type of package that is in the portage tree that satisfies the kernel requirements that some ebuilds have.

Currently portage complains if it finds stuff in package.provided. Can there be a method implemented where the user can just tell portage "don't track my kernel and just install the packages using whatever is in /usr/src/linux".

Maybe a way to do this is to let the user do a: emerge virtual/kernel, or something in that sense (whatever package is virtual for kernel), then this package basically just tells portage to use /usr/src/linux.

The reason this is important is because it gives the user a more efficient way to do kernel upgrades without portage complaining about it not tracking the kernel.